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Friday, July 29, 2016

Q. My apricots were doing
very well as they have for the last several years.After thinning a large crop this year, they
were growing very well and appeared to be getting ready to pick when I opened
the cots, I found the insides to be rotting.I've tried to do a little research without success.

A. This may be ripe fruit
rot, sometimes called Brown fruit rot. It can happen if there is rain near the
time of harvest. We get other diseases on fruit as well if there are rainy
periods at different stages of fruit development.

There is not much you can do except hope that rain does
not occur at that time. Here is some information from the University of
California. See if this description matches your problem.

They recommend fungicide
applications earlier in the season to present it but we get such a little
chance of rain here to me it doesn't make any sense to make these applications.
Just figure this year you had some losses that come along very infrequently.

Q. I
live in Michigan, so our experience with citrus is non-existent, and
there are no experts in our area, but you come recommended as someone
who might be able to give me some advice.
I have a small
potted orange tree with a few leaves that have turned light colored
along the edges. They aren’t yellow or brittle as one might expect in
the case of iron deficiency, but are shiny and flexible like the rest of
the leaves.

I bought the tree on a lark, never expecting it to survive, but it thrives except for these few leaves.

The
plant is outside, on the east side of the house when the temperatures
will stay about 40ºF. The rest of the time (about 7 months a year) it
is inside, on an east facing but brightly lit porch. It has never been
frosted.

The tree has been potted for 2 ½ years. I have
not re-potted it. It is about 14” tall. It was originally potted in
soil that was 50% commercially prepared potting soil and 50% composted
leaves.

Our water is very alkaline, so during the winter I
water with black tea, made with distilled water and fertilize at about
half strength with Miracle Grow. During the summer I water with
rainwater and fertilize with the rest of my plants, again using Miracle
Grow, this time at recommended strength.

Have you any suggestions for me? Any advice would be appreciated.

A. It will be fun for you to grow a citrus in Michigan. I am originally
from Wisconsin so I can understand your interest in having a citrus
growing in Michigan. First of all make sure the container is large
enough for your tree. It will need to be fairly large.

Secondly
the tree should be removed from the container every 2 to 3 years and
wash some of the soil away from the roots. Cut off some of the roots
near the outer edges and repot the citrus in the container using new
potting soil. In two or three years the organic matter content of the
soil in a container will be gone. The soil would become more compact and
the roots of the tree will begin to suffocate. Water will not flow
through the container as easily as before. The air spaces around the
roots collapse. Root rot begins to set in and this usually causes leaves
to start scorching on the edges, yellowing and falling from the tree.
Repotting the tree every 2 to 3 years and trimming off some of the
excess roots helps to keep the tree young and vigorous. Using new soil
increases the air spaces around the roots and helps keep them healthy.
When you take the tree out of the container, look at the roots. Healthy
roots are creamy white. Roots that are beginning to die turn brown.

When
you repot the citrus also reduce the size of the canopy or top of the
tree. Look at stems that are too close together or on top of each other
and remove them totally. Avoid giving the tree a "Butch haircut". You
will generally thin out the branches and open the canopy. If some of the
limbs are too long, cut them back so they are shorter and reshape the
tree.

Leave the citrus out in the container outside as
many months as you possibly can during the spring, summer and fall. They
can take reduced sunlight for maybe two or three months but no longer
than this. It sounds like to me you are keeping them inside too long. If
you have a warm spell during the winter when it's not freezing, put it
outside and let it get lots of sunlight. The tree will store this energy
inside of its trunk and limbs and live off of it for a time when light
level is low and inside the home. If you can put a florescent light
close to it, a few inches away, leave it on for 12 to 14 hours or longer
each day when it's inside. This will help a lot.

A common
problem on citrus are scale insects, usually brown scale. Look for
these brown bumps on leaves and stems. If you find them, use a
horticultural oil and spray the leaves and stems with it about once a
month and you will start to see the populations of this insect decrease.
Brown scale and root rot because of watering too often or poor drainage
and a lack of sunlight are the worst problems.

Q. Could you tell me what these little buggars are and how to eliminate them?

A. This is not a
common pest of fruit. It is an insect that just happened to be in the
area and found something it could eat, had more of its own and decided
you had a place it could set up residence.

I am not an entomologist but
know
enough that I could identify it if it was a common pest. It is not. At
first I thought it was a sap beetle but it is not.

Regardless, the
control is the same. Pick up and dispose of all damaged fruit on fruit
trees and the ground. Compost them or get rid of
them. Once you get rid of their food supply (damaged fruit) they will
begin to disappear.

From the look of them they do not have the ability
to damage fruit themselves (their mouths cannot chew things) they look
for already damaged fruit so they can feed and
multiply.

Q. I noticed numerous
several small bees swarming around one of my brick planters.The bees were not aggressive and small …
about ½ to ¾ inches long.There wasn’t a
hive of any type, but I did notice a small hole (about ¼ in diameter) in the
dirt where the bees would enter and exit.I did some quick internet research and these appear to be type of
Solitary Bee.Attached are two pics of
one that I caught with my pool net…sorry the pictures aren’t very good, but I
was hoping that you could confirm that these are Solitary Bees.They have a black/gray body and the underside
is yellow.

If they are Solitary Bees,
the research I did indicates that they aren’t aggressive, rarely sting, and are
great pollinators.However, they are a
nuisance where they are located.Do you
have any suggestions on how I can get them to move ground nest to another
location without killing them?

One of the solitary bees we frequently see signs of in the garden include the leaf cutter bee.

You can build bee boxes or homes for these bees to use for egg laying by drilling one 2:45 eighths inch holes deeply in large blocks of wood.

A. Joe yes these are
solitary bees. I am no be expert but my understanding is that solitary bees do

not make be colonies, they
do not make sizable amounts of honey, they are not aggressive and they cannot
sting. However, I think they get a late start in the season and so early crops
such as tree fruits may not be the best for them to pollinate. They are better
for pollinating plants that bloom later in the season like summer vegetables
and flowers.

An example of a solitary bee are the leaf cutter bees. You can
attract more bees by putting out clean water. They need water to keep cool,
honeybees in particular to cool their hives. Honeybees are constantly carrying
water back to the hive during hot weather. But the water has to be changed
regularly.

As far as moving them, I don't know any way to move them. I think
many of them lay their eggs in these holes and the young bees emerge from them
later. That is the way with leaf cutter bees so I'm guessing these guys are
similar.

Q. I appear to have a
massive infestation of Cottony Cochineal Scale on my prickly pear cactus. I can
usually get most of it off by hosing, but much is hard to reach. Beyond hosing,
what insecticide or other kind of solutions do you recommend? Permanent, if
possible!

A. Yes, scale is quite
common on cacti in general and prickly pear in particular. This one in particular is most likely cochineal scale rather than cottony cushion scale. This cochineal scale is a close relative of the cochineal scale that was used by the Spaniards in Mexico centuries ago and die making. This scale leaves a purple color on your finger when you rub it.They can be hosed
off the pads with a strong stream of water as you are doing but they reinfest
the pads very quickly and in full force again in a week or two.

When I am growing prickly pear as a food I am more
concerned with insecticides and getting them into the food we eat but if they
are grown just as an ornamental plant and not used for food then I feel better
about using something stronger than water, soap and water sprays.

The problem with a strong stream of water is that the
force from this water is not enough to knock the insect off of the pad, only
the white, fluffy coating surrounding the insect. So it is a short time before it
regrows this protective cover and the unsightly mass of cotton is back again.

Knocking the fluffy covering off first with a strong
stream of water will make these insects more susceptible to an insecticide
spray. Most of the common insecticides will work after that; malathion,
pyrethrins, Sevin, just about any common insecticide will work after the fluffy
covering has been removed. This does not mean they won’t be back. They will.
But it will take longer for them to get established on the plant again.

Q. My grapevine had grapes
for the first of four years but this and last year it had none. What is wrong
with my grape vine? By all appearances it looks perfectly healthy but it didn’t
produce grapes for the last two years.

A. The fruit or berries of
grapevines are produced only on the wood which grew the previous year. Growth this
season and three-year-old wood and older will not produce any fruit. Two-year-old
wood is the only place that can produce flowers and fruit.

If
all of the two-year-old wood is removed or dies, there will be no flowers or fruit.
If the vine is left to grow without any pruning it will produce lots of fruit.
But over the years this tangle of growth will create problems from crowding,
fruit rots, disease, and it will be difficult to harvest the fruit.

Next
spring do not prune. Let the vine grow. At least this way you will get some
fruit from it. Your other option is to learn how to prune grapes correctly.

Q. We have two fig trees
loaded with figs. Problem is they are not ripening. What is our problem or do
they take a long time to ripen?

A. Most of the main crop
of figs is still green in June and have developed to maturity. If the tree is
getting plenty of water, the figs should be enlarging rapidly. If the figs are
not enlarging, then the tree is not getting enough water.

Figs
that produce fruit need a lot of water so that the fruit will enlarge. If you
don't give the tree enough water the fruit will stay small and fall from the
tree, hard as rocks.

Q. I have powdery mildew
on lower branches on my shrubs. Should I remove the dying leaves? Since the
temperature will be 114 tomorrow, should I wait until Fall?

Powdery mildew on Japanese euonymous. These plants are famous for mildew.

A.Powdery mildew on these plants is probably left over
from this wet spring. Powdery mildew disease does not require high humidity. As
far as diseases go, it probably has the lowest requirement for humidity or
moisture.

The usual reasons for powdery mildew besides cloudy,
rainy weather is shade, poor air circulation and poor plant health. If you can
reduce the shade with some light pruning that may help.

Make
sure there is no splashing water from an irrigation system. This will spread
the disease from leaf to leaf or plant to plant.

Sulfur
dusts as well as neem oil have been known to work as preventive sprays.
Otherwise use traditional fungicides that list powdery mildew control on the
label. But with these high temperatures the disease should subside. It is a
cool temperature disease.

If
the leaves look pretty bad, then go ahead and remove them. At least then you
are removing disease inoculum. But consider some light pruning instead. You
won't hurt anything with light pruning this time of year and you may give the
lower parts of the canopy more sunlight.

Q. I found about 4 to 5 tomatoes
with holes in them. I have been getting ripe tomatoes for about 30 days and found
these with holes in them during the last two days. I searched for bugs, eggs
and leaf damage but did not find anything. Any ideas?

Probably tomato fruitworm damage

A. The 3/8-inch diameter
and larger holes in your tomatoes look like damage from the tomato fruit worm.
These are worms, or caterpillars, are about an inch and a half long and 3/8 of
an inch wide. They eat holes mostly in tomato fruit, usually when they are
green or when they turn red but are still hard or firm. Frequently the fruit
becomes rotten from these holes.

Organic
sprays of Bt or Spinosad when the fruits are starting to form will prevent
this.

Q. We have a concern about
our Saguaro planted in 1988. It now has three large arms and we recently
noticed a crack on the outside of one arm at the bend of the “elbow”.

Saguaro growing near Parker, Arizona

A. Don't water it too
often. Watering about 10 or 15 gallons around the base of the plant in a 5 to 6 ft radius once a
month is enough. Those plants expand like an expanding accordion when they
swell up with water.

Let
them use this water before you give them another drink. The plants will shrink
in size when they use their internal water supply. If they are given water too
often they can swell up and split. The splitting may have happened during the
rains this spring and early summer. Regardless, the crack should heal and give
the plant a little bit of character.

Q. I have a healthy Yucca
tree (10 years old) in my desert landscaped yard (similar but smaller to what
is pictured below). The homeowner before me watered it daily in summer and
weekly in winter along with the rest of the drought-resistant plants in the yard
and did so for many, many years. I have continued that practice but have read
that Yuccas should not have daily watering. Since everything looks healthy and
vibrant, would it be OK to continue daily watering in summer? Thanks.

A. Exactly right. They are
not supposed to be watered this way. However it appears the previous owner
found a happy medium between watering frequently and not watering too much. My
guess is the tree was getting very small amounts of water daily. I would not
worry about it if the plants are doing okay and I wouldn't change anything.
However, you should be aware that you are doing it entirely wrong but it's
working. Be careful if you change anything because these plants are now
adjusted to that watering schedule.

Q. I am concerned about
one of my three Bougainvillea plants growing on the south side. I removed some very old and scraggly
oleanders from this spot and raked out all the oleander leaves before planting
these Bougainvillea. I feed them and
they have good water supply, but the one in the center is scrappy looking while
its brothers on either side are thriving.

Bougainvillea grown as a woody perennials shrub in Bullhead city, Arizona where it seldom freezes.

A. Bougainvillea do very
well here during our summer heat with a minimal amount of care as long as the
soil is amended at the time of planting and they are fed regularly with low
nitrogen fertilizers.

They
like to be pruned so if you see them struggling, prune them back, give them
water and fertilize them lightly with a rose or tomato fertilizer.

They
also bloom better if they are struggling rather than if they are pampered too
much. Going through a dry period may encourage blooming.

Welcome to Xtremehorticulture

Home. My home base is Las Vegas, Nevada, in the Eastern Mojave Desert. This blog focuses on horticulture in Deserts.

Me. Desert Horticulture is very different from horticulture in wet climates. Very few people talk about it. This blog focuses on it. My experience in horticulture span over 50 years; time as an applied academic and now working as a consultant. This blog shares my experience and advice in Desert Horticulture. Work in Northern, East and Southern Africa, Western and Central Asia and the Middle East have expanded my views on Desert Horticulture.

Questions. I reply to questions sent to me as quickly as possible. Please include pictures. It helps. Unless questions are confidential, I post them on this blog if they add new information.